The Genetic Diversity and Dysfunctionality of Catalase Associated with a Worse Outcome in Crohn's Disease.

Chronic gut inflammation in Crohn's disease (CD) is associated with an increase in oxidative stress and an imbalance of antioxidant enzymes. We have previously shown that catalase (CAT) activity is permanently inhibited by CD. The purpose of the study was to determine whether there is any relationship between the single nucleotide polymorphisms (SNPs) in the CAT enzyme and the potential risk of CD associated with high levels of oxidative stress. Additionally, we used protein and regulation analyses to determine what causes long-term CAT inhibition in peripheral white mononuclear cells (PWMCs) in both active and inactive CD. We first used a retrospective cohort of 598 patients with CD and 625 age-matched healthy controls (ENEIDA registry) for the genotype analysis. A second human cohort was used to study the functional and regulatory mechanisms of CAT in CD. We isolated PWMCs from CD patients at the onset of the disease (naïve CD patients). In the genotype-association SNP analysis, the CAT SNPs rs1001179, rs475043, and rs525938 showed a significant association with CD (p < 0.001). Smoking CD patients with the CAT SNP rs475043 A/G genotype had significantly more often penetrating disease (p = 0.009). The gene expression and protein levels of CAT were permanently reduced in the active and inactive CD patients. The inhibition of CAT activity in the PWMCs of the CD patients was related to a low concentration of CAT protein caused by the downregulation of CAT-gene transcription. Our study suggests an association between CAT SNPs and the risk of CD that may explain permanent CAT inhibition in CD patients together with low CAT gene and protein expression.

Transcriptomic identification of TMIGD1 and its relationship with the ileal epithelial cell differentiation in Crohn's disease.

Crohn's disease (CD) is a complex and multifactorial illness. There are still considerable gaps in our knowledge regarding its pathophysiology. A transcriptomic approach could shed some light on little-known biological alterations of the disease. We therefore aimed to explore the ileal transcriptome to gain knowledge about CD. We performed whole transcriptome gene expression analysis on ileocecal resections from CD patients and inflammatory bowel disease-free controls, as well as on a CD-independent cohort to replicate selected results. Normalized data were hierarchically clustered, and gene ontology and the molecular network were studied. Cell cultures and molecular methods were used for further evaluations. Genome-wide expression data analysis identified a robust transmembrane immunoglobulin domain-containing 1 (TMIGD1) gene underexpression in CD tissue, which was even more marked in inflamed ileum, and which was replicated in the validation cohort. Immunofluorescence showed TMIGD1 to be located in the apical microvilli of well-differentiated enterocytes but not in intestinal crypt. This apical TMIGD1 was lower in the noninflamed tissue and almost disappeared in the inflamed mucosa of surgical resections. In vitro studies showed hypoxic-dependent TMIGD1 decreased its expression in enterocyte-like cells. The gene enrichment analysis linked TMIGD1 with cell recovery and tissue remodeling in CD settings, involving guanylate cyclase activities. Transcriptomics may be useful for finding new targets that facilitate studies of the CD pathology. This is how TMIGD1 was identified in CD patients, which was related to multiciliate ileal epithelial cell differentiation.NEW & NOTEWORTHY This is a single-center translational research study that aimed to look for key targets involved in Crohn's disease and define molecular pathways through different functional analysis strategies. With this approach, we have identified and described a novel target, the almost unknown TMIGD1 gene, which may be key in the recovery of injured mucosa involving intestinal epithelial cell differentiation.

Nivolumab-induced immune-mediated colitis: an ulcerative colitis look-alike-report of new cases and review of the literature.

PURPOSE: Nivolumab, a monoclonal antibody-targeting programmed cell death protein-1, is being increasingly used for the treatment of some advanced neoplasms. Several of its adverse effects are a result of the upregulation of T cells, with colitis as one of the most severe, and a challenging differential diagnosis with ulcerative colitis. However, few real-life clinical practice cases have been reported beyond trials. Our aim was to report a series of new cases, reviewing previously communicated endoscopic-proven nivolumab-induced colitis. METHOD: All patients treated with nivolumab in three university centers were identified and those who developed immune-mediated colitis (defined as the presence of diarrhea and evidence of colitis demonstrated by colonoscopy) were described. Additionally, a review of case reports of nivolumab-induced colitis reported in the literature up to March 2018 was performed. RESULTS: Six new cases of nivolumab-induced colitis and 13 previously reported cases out of randomized clinical trials are described. Colonoscopy showed a mucosal pattern mimicking ulcerative colitis in a large proportion of patients. Clostridium difficile superinfection was observed in two out of 19 cases. All but three patients definitively discontinued nivolumab therapy. Most patients were initially managed with oral or intravenous corticosteroids, but five of them required rescue therapy with infliximab. CONCLUSIONS: Nivolumab-induced colitis may mimic ulcerative colitis. Steroid therapy (oral or intravenously) is often efficient, but one-fourth of patients need rescue therapy with anti-TNF. Intestinal superinfection with Clostridium difficile or cytomegalovirus should be ruled out before starting immunosuppressive therapy.

Serial semi-quantitative measurement of fecal calprotectin in patients with ulcerative colitis in remission.

BACKGROUND: Fecal calprotectin (FC) correlates with clinical and endoscopic activity in ulcerative colitis (UC), and it is a good predictor of relapse. However, its use in clinical practice is constrained by the need for the patient to deliver stool samples, and for their handling and processing in the laboratory. The availability of hand held devices might spread the use of FC in clinical practice. OBJECTIVES: To evaluate the usefulness of a rapid semi-quantitative test of FC in predicting relapse in patients with UC in remission. MATERIALS AND METHODS: Prospective, multicenter study that included UC patients in clinical remission for ≥6 months on maintenance treatment with mesalamine. Patients were evaluated clinically and semi-quantitative FC was measured using a monoclonal immunochromatography rapid test at baseline and every three months until relapse or 12 months of follow-up. RESULTS: One hundred and ninety-one patients had at least one determination of FC. At the end of follow-up, 33 patients (17%) experienced clinical relapse. Endoscopic activity at baseline (p = .043) and having had at least one FC > 60 µg/g during the study period (p = .03) were associated with a higher risk of relapse during follow-up. We obtained a total of 636 semi-quantitative FC determinations matched with a three-month follow-up clinical assessment. Having undetectable FC was inversely associated with early relapse (within three months), with a negative predictive value of 98.6% and a sensitivity of 93.9%. CONCLUSIONS: Serial, rapid semi-quantitative measurement of FC may be a useful, easy and cheap monitoring tool for patients with UC in remission.

Therapeutic requirements in active ulcerative proctitis: A single-centre study.

BACKGROUND: Ulcerative proctitis (UP) presents distinctive clinical characteristics, outcomes and therapeutic approaches as compared to left-sided and extensive ulcerative colitis (UC). AIM: To describe the current therapeutic requirements and clinical outcomes in patients with active UP. METHODS: Retrospective observational study conducted in a referral IBD centre. Patients with UP in follow-up between 1989 and 2014 were included. The clinical characteristics, as well as the different treatments and drug formulations administered to treat flares, were recorded. RESULTS: Out of 687 UC patients, 101 patients (15%) with UP were included. Median follow-up was 8 years (IQR 3-14) and 49% of patients presented disease activity during the study period. Topical mesalazine monotherapy (90%) was the most commonly administered treatment for disease activity (mostly as suppositories), followed by topical steroids (47%) and oral mesalazine (56%) in monotherapy or combination therapy. Only 14% and 16% of patients required oral prednisone and beclomethasone, respectively. CONCLUSIONS: In clinical practice, active UP presents mostly favourable outcomes. Mesalazine suppositories are by far the most used treatment for these patients.

Identification of risk loci for Crohn's disease phenotypes using a genome-wide association study.

BACKGROUND & AIMS: Crohn's disease is a highly heterogeneous inflammatory bowel disease comprising multiple clinical phenotypes. Genome-wide association studies (GWASs) have associated a large number of loci with disease risk but have not associated any specific genetic variants with clinical phenotypes. We performed a GWAS of clinical phenotypes in Crohn's disease. METHODS: We genotyped 576,818 single-nucleotide polymorphisms in a well-characterized cohort of 1090 Crohn's disease patients of European ancestry. We assessed their association with 17 phenotypes of Crohn's disease (based on disease location, disease behavior, disease course, age at onset, and extraintestinal manifestations). A total of 57 markers with strong associations to Crohn's disease phenotypes (P < 2 × 10(-4)) were subsequently analyzed in an independent replication cohort of 1296 patients of European ancestry. RESULTS: We replicated the association of 4 loci with different Crohn's disease phenotypes. Variants in MAGI1, CLCA2, 2q24.1, and LY75 loci were associated with a complicated stricturing disease course (Pcombined = 2.01 × 10(-8)), disease location (Pcombined = 1.3 × 10(-6)), mild disease course (Pcombined = 5.94 × 10(-7)), and erythema nodosum (Pcombined = 2.27 × 10(-6)), respectively. CONCLUSIONS: In a GWAS, we associated 4 loci with clinical phenotypes of Crohn's disease. These findings indicate a genetic basis for the clinical heterogeneity observed for this inflammatory bowel disease.

An overview of the natural history of inflammatory bowel diseases.

Inflammatory bowel disease includes two main conditions: Crohn's disease (CD) and ulcerative colitis (UC). Natural history studies of these two entities have shown relevant differences in several clinical outcomes, mainly a more chronic and persistent (although often subclinical) inflammatory activity and the development of complications related to long-term tissue damage in CD. This led in recent years to different long-term therapeutic strategies in each disease. In this article, we review the main phenotypic features of UC and CD at the time of disease diagnosis and their changes along the course of the disease, as well as their consequences regarding drug therapy and surgical requirements.

Addition of mesalazine for subclinical post-surgical endoscopic recurrence of Crohn's disease despite preventive thiopurine therapy: A case-control study.

BACKGROUND AND AIM: Thiopurines prevent Crohn's disease (CD) endoscopic recurrence (ER) at least in 50% of patients 1 year after surgery. This study aimed to evaluate the value of adding mesalazine in patients with subclinical ER despite preventive thiopurine therapy. METHODS: Crohn's disease patients with ileocecal resection treated with thiopurines for postsurgical recurrence prevention in whom mesalazine was added (cases) to treat ER without clinical recurrence (CR) were identified and compared with those in whom no treatment was added to thiopurines (controls). All patients were followed up for at least 1 year from the index endoscopy. Development of CR as well as evolution of mucosal lesions was evaluated. RESULTS: Thirty-seven patients were included (19 cases and 18 controls). Initial Rutgeerts' score was i2 in 16 patients (9 cases and 7 controls), and i3 in 21 patients (10 cases and 11 controls). After a median clinical follow-up of 59 months (interquartile range 22-100) from the index endoscopy, six cases (32%) and two controls (11%) developed CR (P = 0.2). After a median time to last endoscopic follow-up of 23 months (interquartile range 17-71), 18 patients (49%) showed improvement in Rutgeerts' score, 11 patients (30%) demonstrated progression of mucosal lesions, and 8 (22%) had no changes, with no differences between study groups. CONCLUSIONS: The addition of mesalazine seems to be of no benefit in patients with subclinical endoscopic recurrence while on thiopurine prevention. Moderate endoscopic postsurgical recurrence while on thiopurines may even revert with no additional therapy in some patients.

Biomarkers for diagnosis and monitoring of celiac disease.

Celiac disease (CD) is an autoimmune disorder, which damages the small intestine and is caused by ingestion of gluten in genetically susceptible individuals. The only known effective treatment is a lifelong gluten-free diet. Genetic risk factors have been identified and nearly all patients are HLA-DQ2 and/or HLA-DQ8 positive. Specific autoantibodies, IgA antitissue transglutaminase-2, antiendomysium, and antideaminated forms of gliadin peptide antibodies, are widely used as diagnostic aids in celiac patients. However, the discovery of new biomarkers may help in the diagnosis and follow-up of the disease. Recently, the molecule REG Iα, involved in tissue regeneration, has been proposed as a new biomarker of CD. REG Iα expression is increased in the target tissue and in the sera of celiac patients during damage and inflammation, decreasing after gluten-free diet. In this article we review the main biomarkers for diagnosis and monitoring of CD, focusing on the immune response-related mechanisms.

Urinary levels of regenerating protein Iα do not differentiate celiac patients and healthy subjects.

Celiac disease is an autoimmune disorder induced by gluten in genetically predisposed people. The discovery of new biomarkers may help in the diagnosis and follow-up of celiac patients. Regenerating islet-derived 1 alpha (REGIα)--a biomarker related to tissue regeneration--is increased in serum at the onset of the disease, decreasing after gluten-free diet (GFD). As REGIα is a 18 kDa soluble glycoprotein, it may be detected in urine samples, increasing in celiac patients. We have determined REGIα levels by ELISA. No differences were found among patients (onset or after GFD) and controls and no correlation exists among REGIα in sera and urine.

Fecundity, pregnancy outcomes, and breastfeeding in patients with inflammatory bowel disease: a large cohort survey.

AIM: The aim was to assess the impact of inflammatory bowel disease (IBD) and its treatment on fertility, pregnancy outcomes, and breastfeeding. IBD is a chronic inflammatory condition that is usually diagnosed in young adulthood. Patients are often concerned about fertility and pregnancy outcomes. METHODS: A structured questionnaire was posted to 850 adults with IBD followed-up on in a single center. RESULTS: A total of 503 patients (59%) with a median age of 40 years and equally distributed for gender and type of IBD returned the questionnaire. Overall, 71% of the patients had a total of 659 children, 36% of whom were born after the diagnosis. A total of 132 miscarriages were registered, 46% after the diagnosis of IBD. Most childless patients stated that having no children was a personal decision, and only 6% of them were evaluated and diagnosed with infertility. Pregnancies after diagnosis of IBD had a higher probability of caesarean section and preterm delivery. IBD-related drug therapy was discontinued in 16% of the pregnancies, mainly as a result of medical advice. Babies born after the diagnosis of IBD were less often breastfed. CONCLUSIONS: The infertility rate among IBD patients seems to be similar to that seen in the general population. However, a large proportion of patients chose to remain childless. Vaginal delivery and breastfeeding are less likely to occur in babies born after the diagnosis. Suitable information for patients to avoid unwarranted concerns about adverse reproductive outcomes, as well as improved obstetrical and perinatal management, still seems to be necessary.

A systematic review of SAPHO syndrome and inflammatory bowel disease association.

BACKGROUND: The association between inflammatory bowel disease (IBD) and synovitis, acne, pustulosis, hyperostosis, osteitis syndrome (SAPHO syndrome) was first reported in 1992. To date, only case reports and short series have been published. AIMS: The purpose of this study was to report new cases and systematically review the literature on this association. MATERIALS AND METHODS: All patients with concomitant diagnosis of SAPHO syndrome and IBD were identified from the databases of the rheumatology and gastroenterology departments of our institution. In addition, we systematically searched for published full articles in Medlars Online International Literature via PubMed. Relevant information of each positive match was collected and all authors were contacted for additional clinical data. RESULTS: Three patients sharing both SAPHO syndrome and IBD were identified among the 62 patients with SAPHO syndrome (4.8 % of the SAPHO cohort) and the 1,309 patients with IBD (0.2 % of the IBD cohort) from our hospital database. After a systematic review, a total of 39 reported patients with concomitant diagnosis of SAPHO syndrome and IBD were identified. There was a female predominance and most had Crohn's disease with colonic involvement. CONCLUSIONS: The association of SAPHO syndrome and IBD seems to be rare among IBD patients but not so among SAPHO patients. SAPHO could be underdiagnosed because of the similarity of its clinical manifestations and some more common extraintestinal manifestations or drug-related side effects in IBD.

Predictors of favourable outcome in inflammatory Crohn's disease. A retrospective observational study.

BACKGROUND: No studies have specifically searched for predictors of a favourable outcome that would allow a conservative therapeutic approach in adult Crohn's disease (CD). AIMS: To identify predictors of a favourable disease course over time at CD diagnosis. METHODS: We identified and included all patients diagnosed with CD between January 1994 and December 2003, who had CD with an inflammatory pattern and no perianal disease at diagnosis, and who were followed up for at least 5 years. Clinical and therapeutic features until December 2008 and losses to follow-up were identified. We defined a favourable outcome as the absence of stricturing and penetrating complications of the disease (including perianal disease), together with the absence of need for anti-TNF therapy or resectional surgery during follow up. RESULTS: One hundred and forty-five patients were included and followed up for a median of 96 months (IQR, 79-140). At diagnosis, location was ileal in 39%, colonic in 28%, and ileocolonic in 32%; 50% of the patients were active smokers, and 41% used immunomodulators. Eighty-two patients (57%) met the criteria for a favourable outcome at the end of follow-up. The only factor associated with a favourable outcome was isolated colonic involvement (P=0.022), with 73% of these patients meeting the criteria for a favourable outcome. CONCLUSIONS: A favourable outcome of initially uncomplicated CD is not easily predicted at disease diagnosis by means of clinical or epidemiologic factors. Nevertheless, patients with isolated colonic disease are less likely to have an aggressive course.

Orthotopic murine xenograft model of uveal melanoma with spontaneous liver metastasis.

Uveal melanoma is the most common intraocular malignancy in adults. Despite the effective primary treatment, up to 50% of patients with uveal melanoma will develop metastatic lesions mainly in the liver, which are resistant to conventional chemotherapy and lead to patient's death. To date, no orthotopic murine models of uveal melanoma which can develop spontaneous metastasis are available for preclinical studies. Here, we describe a spontaneous metastatic model of uveal melanoma based on the orthotopic injection of human uveal melanoma cells into the suprachoroidal space of immunodeficient NSG mice. All mice injected with bioluminescent OMM2.5 ( n = 23) or MP41 ( n = 19) cells developed a primary tumor. After eye enucleation, additional bioluminescence signals were detected in the lungs and in the liver. At necropsy, histopathological studies confirmed the presence of lung metastases in 100% of the mice. Liver metastases were assessed in 87 and in 100% of the mice that received OMM2.5 or MP41 cells, respectively. All tumors and metastatic lesions expressed melanoma markers and the signaling molecules insulin-like growth factor type I receptor and myristoylated alanine-rich C-kinase substrate, commonly activated in uveal melanoma. The novelty of this orthotopic mouse xenograft model is the development of spontaneous metastases in the liver from the primary site, reproducing the organoespecificity of metastasis observed in uveal melanoma patients. The faster growth and the high metastatic incidence may be attributed at least in part, to the severe immunodeficiency of NSG mice. This model may be useful for preclinical testing of targeted therapies with potential uveal melanoma antimetastatic activity and to study the mechanisms involved in liver metastasis.

Omega-3 fatty acids and inflammatory bowel diseases - a systematic review.

BACKGROUND & AIM: Despite their well known anti-inflammatory actions, the clinical usefulness of omega-3 PUFA in inflammatory bowel disease is controversial. We aimed to systematically review the available data on the performance of omega-3 PUFA as therapeutic agents in these patients. METHODS: Electronic databases were systematically searched for RCT of fish oil or omega-3 PUFA therapy in both active and inactive ulcerative colitis or Crohn's disease, without limitation on either the length of therapy or the form it was given, including nutritional supplements and enteral formula diets. Eligible articles were assessed for methodological quality on the basis of the adequacy of the randomisation process, concealment of allocation, blinding of intervention and outcome, possible biases, and completeness of follow-up. The five-point Oxford quality score was calculated. RESULTS: A total of 19 RCT were finally selected for this review. Overall, available data do not allow to support the use of omega-3 PUFA supplementation for the treatment of both active and inactive inflammatory bowel disease. Negative results are quite consistent in trials assessing the use of omega-3 PUFA to maintain disease remission, particularly ulcerative colitis, and to a lesser extent Crohn's disease. Trials on their use in active disease do not allow to draw firm conclusions mainly because the heterogeneity of design (ulcerative colitis) or their short number (Crohn's disease). In most trials, the appropriateness of the selected placebo is questionable. CONCLUSION: The present systematic review does not allow to make firm recommendations about the usefulness of omega-3 PUFA in inflammatory bowel disease.

Bacteria and spontaneous experimental colitis: immunological changes.

BACKGROUND: Intestinal commensal flora seems to be a requisite for both human and experimental intestinal inflammation. Our aim was to assess the immunological changes in the colon of IL-10(-/-) mice depending on the environmental conditions. MATERIALS AND METHODS: Twelve wild-type (WT) and 24 IL-10(-/-) 4-week-old mice were kept under specific pathogen-free (SPF) conditions for 4 weeks. Half of them were transferred to a conventional environment. Mice were sacrificed at 12 weeks of age, and the incidence and severity of colitis was assessed. Intraepithelial (IEL) and lamina propria (LPL) lymphocytes were assessed for phenotype and apoptosis by flow cytometry. Toll-like receptors 2 (TLR2) and TLR9 expression was assessed by real-time PCR. Immunohistochemical analyses for cell apoptosis, TLR2 and MyD88 were also performed. RESULTS: IL-10(-/-) mice shifted to conventional conditions showed a greater incidence (66% vs. 50%) and severity of colitis than animals kept under SPF conditions (P = 0·009). The number of CD3+ IEL was higher and their apoptosis rate lower in IL-10(-/-) than in their WT counterparts, regardless of the environment. In LPL, however, these differences were only observed in mice shifted to conventional conditions. TLR2 expression was significantly increased in SPF-housed IL-10(-/-) mice when compared to WT controls. Immunohistochemistry demonstrated the loss of TLR2 and MyD88 in damaged areas. CONCLUSIONS: In SPF conditions, IL-10 deficiency appears to be compensated by an increased epithelial TLR2 expression, thus resulting in a milder colonic damage. However, in conventional conditions, this compensatory mechanism would be exceeded inducing a more severe colonic damage with activation of LPL immune cells.

Therapeutic effect of antisecretory factor-rich egg yolk on the late phases of 2,4,6-trinitrobenzenesulphonic acid colitis in mice.

Antisecretory factor (AF) is expressed in all tissues of mammals, inhibits intestinal hypersecretion and has anti-inflammatory properties as well. Endogenous AF synthesis may be stimulated by feeding hydrothermally processed cereals. Alternatively, freeze-dried egg yolk can be used as a source of exogenous AF. Several reports have suggested that AF from freeze-dried egg yolk may be useful in inflammatory bowel disease. We assessed the effect of freeze-dried, AF-rich egg yolk intake on 2,4,6-trinitrobenzenesulphonic acid (TNBS) colitis. Balb/c mice were randomised to receive (1) AF in sterile drinking-water (4 g/l, n 38) and (2) sterile drinking-water alone (vehicle, n 38) from TNBS or saline administration onwards. Different subsets of mice were killed at weeks 1-3 after TNBS or saline administration. Macroscopic and microscopic damage was assessed in colonic specimens. Eicosanoid and cytokine production was evaluated in supernatants of 24 h-incubated colonic explants. Myeloperoxidase activity was measured in frozen colonic samples, while apoptosis was assessed in paraffined samples by the in situ oligoligation method. AF-treated mice showed a milder colonic damage compared with the vehicle group, which became statistically significant at week 3. This was accompanied by decreased IL-2, IL-1 and leukotriene B4 production at weeks 2 and 3, as well as increased interferon-γ at week 1, in AF-treated mice compared with vehicle-treated mice. AF-treated mice had significantly increased counts of apoptotic cells in the lamina propria at weeks 1 and 2 post-TNBS. In conclusion, the administration of AF-rich egg yolk has a therapeutic effect in the late phases of TNBS colitis in Balb/c mice.

Irritable bowel syndrome: can nutrient manipulation help?

PURPOSE OF REVIEW: To describe the evidences for the usefulness of dietary manipulations (including the use of probiotics and prebiotics) in the management of irritable bowel syndrome (IBS). RECENT FINDINGS: Exclusion diets do not have a role in the management of these patients except in the case of malabsorbed sugars (lactose, fructose). However, recent work suggests that excluding these sugars is more effective in non-IBS than in IBS patients. Also, the first small open series on the use of very low (20 g/day) carbohydrate diet (VLCD) in IBS has been published with promising results. However, safety concerns do not allow us to recommend them. In the period of review, further evidence has been provided on the role of psyllium in IBS. Also, the available evidence on the use of probiotics in IBS has been meta-analyzed. SUMMARY: IBS patients should eat a balanced diet without restrictions, and (except for malabsorbed sugars) exclusion diets are not useful in most of them. The role of VLCD remains to be established. The concept that increasing fiber intake is useful for IBS may not be true for all patients, and hydrophilic colloids (e.g. psyllium) are preferred. There is growing evidence for the effectiveness of probiotics in IBS.

Rat CCl(4)-induced cirrhosis plus total portal vein ligation: a new model for the study of hyperammonaemia and brain oedema.

INTRODUCTION: Animal models used to study hyperammonaemic disorders related to chronic liver disease are unsatisfactory. These animals only develop hyperammonaemia and brain oedema when fed with diets supplemented with amonium acetate. AIM: To develop a novel experimental model of hyperammonaemia and brain oedema in CCl(4)-induced cirrhosis in rats. METHODS: Four groups were studied: rats with sham intervention (S), rats with total portal vein ligation (TPVL), cirrhotic rats (LC), and cirrhotic rats with TPVL (LC+TPVL). When ascites was diagnosed, oral glutamine challenge (OGC) test was performed. Blood, liver, lungs and brain samples were collected to quantify liver function parameters, plasmatic and cerebral ammonia, endotoxaemia, liver and brain histology, brain oedema and portosystemic shunting degree. RESULTS: LC+TPVL rats showed a significant increase in portosystemic shunting when compared with LC group and a significant derangement in liver function when compared with TPVL group. These alterations resulted in a significant increase in plasmatic and brain ammonia concentrations and a higher plasmatic endotoxaemia as compared with others. Similarly, the area under OGC curve was significantly increased in LC+TPVL group as compared with the others, and correlates with portal shunting. Low-grade brain oedema was only observed in LC+TPVL group. All cirrhotic groups showed liver regeneration nodules and type-II Alzheimer astrocytes CONCLUSION: LC+TPVL reproduce the main alterations - portosystemic shunting, plasmatic and cerebral hyperammonaemia and low-grade brain oedema - observed in cirrhotic patients with hepatic encephalopathy.